1. Field of the Invention
This invention relates generally to automotive tools, specifically to a pin unseating tool for unseating tapered pins.
2. Prior Art
A typical motor vehicle has many parts in its suspension and steering system that are connected by tapered pins seated in tapered sockets. E.g., in the steering system, the tie rod end has an integral, tapered pin with a threaded tip. The pin is seated in a tapered through-hole or socket at the end of an "Ackermann" arm. The threaded tip of the pin extends out the back of the "Ackermann" arm, so that a nut screwed thereon tightens it in the socket. The tapers on both the pin and the socket are exactly complementary, so that a very tight fit is achieved for preventing the pin from loosening. Many other parts in a vehicle, as well as other machinery, are connected with similar pins and sockets.
However, when these parts need to be separated for servicing or replacement, the tight fit, which works so well for preventing inadvertent loosening, also works to make the separation of the parts very difficult. For a tie rod end, a "pickle fork" is typically used for separating it from the "Ackermann" arm. A "pickle fork" is a tool with a handle and two prongs extending therefrom for positioning around a pin. The prongs have tapering upper and lower surfaces, so that they can be manually forced between the tie rod end and the "Ackermann" arm to separate them by leveraging the handle. This is a difficult and tiring method at best.
Other devices for removing other types of pins and work pieces have also been proposed. U.S. Pat. No. 3,964,152 to Shankwitz et al. (1976) shows an apparatus with a tapered pin seated in a tapered cup that completely encloses the distal end of the pin. A threaded hole in the center of the socket allows a bolt to be wrenched in therethrough to force the pin out of the socket. This apparatus forms a complete system in itself, so that no part of it can be used for unseating other types of pins, such as tie rod end pins.
U.S. Pat. No. 4,852,231 to Turner (1989) and U.S. Pat. No. 4,989,310 to Choat (1991) show pin removal devices that each includes a frame with a hole on a top side thereof. A work piece is placed against the frame, and the pin aligned with the hole. A hydraulic jack or ram is used to push the pin out of the work piece, and through the hole in the frame. These devices can only unseat pins that are not fixedly attached to anything else. They cannot be used for unseating pins such as tie rod end pins, because the tie rod ends cannot be pushed through the hole in the frame.
U.S. Pat. No. 3,861,250 to Zugai (1975) shows a tool for loosening frozen bolts. It includes a shaft for being fitted to an air impact hammer that provides a strong vibrating force. A socket fitted to the end of the shaft applies the vibrating force on a frozen bolt to loosen it. The socket has an interior contour for preventing rotational slippage. Although the socket can physically fit over the tip of a tie rod end pin, the strong vibrating force will cause it to bounce off the pin, or damage the thread by scraping the thread with its rim.